Antarctic sea ice had barely changed from where it was 100 years ago, scientists have discovered, after pouring over the logbooks of great polar explorers such as Robert Falcon Scott and Ernest Shackleton.

Experts were concerned that ice at the South Pole had declined significantly since the 1950s, which they feared was driven by man-made climate change.

But new analysis suggests that conditions are now virtually identical to when the Terra Nova and Endurance sailed to the continent in the early 1900s, indicating that declines are part of a natural cycle and not the result of global warming.

Scott’s ship the Terra Nova

It also explains why sea ice levels in the South Pole have begun to rise again in recent years, a trend which has left climate scientists scratching their heads.